Modern data processing systems are frequently portable devices. For example, a laptop computer may be operated on battery power, rather than plugged into an A/C outlet. Batteries have a finite charge during which the data processing system may be operated. Once the battery is drained, no further operation of the system is possible without using a different battery or connecting the system to A/C power to recharge the battery. Managing and extending battery life is an important design consideration for such devices.
Many different kinds of applications can be run on a portable data processing system, such as video games, spreadsheets, web browsers, and others. Depending on the application, a responsive display is more or less important. For example, a fast-paced video game may become unplayable if the display is not highly responsive. On the other hand, a user performing an analysis on a spreadsheet might not even notice a less responsive display (i.e., display has a lower refresh rate). Refreshing a display (e.g., an LCD panel coupled to a laptop computer) consumes power every time it is performed. Over time, refreshing the display less frequently consumes less power.